1. Field of the Invention
This invention relates to cable support mechanisms, and more particularly, to a support mechanism for diving bell umbilicals.
2. Description of the Prior Art
Diving bells are frequently used in connection with industrial or research operations requiring personnel to carry out duties at locations under water. Such a diving bell provides a pressurized and water tight environment in which men may safely work at extreme water depths.
A diving bell operation is typically conducted from a support vessel anchored at sea. Men and equipment are placed into the diving bell and the bell is lowered to the desired water depth.
A common practice is to support the diving bell from a steel cable attached to a wench, the wench being used to raise and lower the diving bell. Life support lines, which supply electrical power, air, communications circuits, and the like, must also pass from the support ship to the diving bell. The life support lines are commonly banded together into one cable, and that cable inturn is banded to the steel support cable as the diving bell is lowered.
The presence of these life support lines, known as the umbilical cable, presents some difficulty in raising and lowering the diving bell. Because such lines are relatively fragile and subject to damage through kinking, twisting, or stretching, it is important to carefully control the manner in which the umbilical is employed or collected as the diving bell is lowered or raised.
In the past, one method which has been employed is to manually feed the umbilical over the side of the support ship as the diving bell is lowered, and to manually coil or collect the umbilical on deck as the diving bell is raised. Since the umbilical line tends to be relatively large and heavy, however, manual handling of the line is difficult and frequently is not adequate.
Another method of controlling the umbilical involves storing the umbilical on a drum which is rotated by a wench. In order to accommodate the rotary motion of the drum, however, this method makes it necessary to connect each support line to its source through a slip ring and collector arrangement. Because such slip rings and collectors may leak or fail, this method may degrade the safety and reliability of the diving operation. Consequently, a need has developed in the art for a safe, reliable, and mechanized apparatus for controlling the umbilical cable for a diving bell.
Therefore, it is a feature of this invention to provide an umbilical conveyor system which obviates the need for slip rings and collectors within the diving bell life support lines.
It is another feature of this invention to provide an umbilical conveyor system which establishes an adjustable pull on the umbilical so that the umbilical is fed or collected at a rate commensurate with the speed at which the diving bell is lowered or raised.
It is an additional feature of this invention to provide an umbilical conveyor system which will grip the umbilical and may provide an auxiliary means of support for the diving bell in the event the support cable is broken.
It is also a feature of this invention to provide an umbilical conveyor system which guides the umbilical around a predetermined minimum radius of curvature, thereby preventing crimping, twisting, binding, and kinking, and the like, of the life support lines.
It is yet another feature of this invention to provide an umbilical conveyor system which is rotatably and laterally adjustable to accommodate variations in the location of the diving bell and the storage location for the umbilical.